Refrigerating apparatus



Oct. 3l, 1944. A, A.. MCCORMACK 2,361,855

ARFRIGERA'I'ING' AIVPARTUS Filed May 28,. 1941 y :s sheets-sheet 1 uml 3 Sheets-Sheet 2 A. A. MCCORMACK l REFRIGER-ATING APPARATUS Filed May 28, 1941 o cr. 31, 1944.

lvuhu Y .Ai v Q ct. 3l, 1944. A, A, MCCORMYAciK 2,361,855

REFRIGERATING APPARATUS Filed may 28, 1941 s sheets-sheet s Patented Oct. 3l, 1944 BEFRIGERATING APPARATUS Alex A. McCormack, Dayton, Ohio, assignor to GeneralMotors Corporation, Dayton, Ohio, a

' oorporationof Delaware Application May 2s, i941, serial No. 395,847

(crea-11's) y '17 Claims.

This invention relates to refrigerating apparatus and more particularly to improvements in the construction and method and assembling a completely enclosed refrigeration system, One object of this invention is to provide a small refrigeration unit in which the compresson condenser and the evaporator are all mounted within a single casing.

'Another object of this invention is to provide an improved oiling arrangement for use in a refrigeration` system in which the compressorcasing is too small to serve as an oil'reservoir.l

Another object of this invention is to provide a small compact compressor unit which may be operated at very high speeds and also at very low speeds.

Another object of this invention is to provide an improved shaft seal suitable for use in a compressor operated at varying speeds.-

Still another object is to providea shaft seal cooling arrangement in which the refrigerating capacity of the refrigerant entrained by the lubricant may be used to the fullest advantage in cooling the shaft seal.

Still another object of this invention is to provide an improved means for controlling the' return of refrigerant Vfrom the evaporator to the compressor in a system in which the compressor is driven at widely varying speeds without any regard for refrigeration requirements;

- Further objects and advantages of the present invention will be apparent from the following description, reference being ha'd to the accom-'- panying drawings, wherein@ preferred form of the present invention is clearly shown.

In the drawings: Fig. l diagrammatlcally shows my invention as applied to a conventional passenger automobile; Fig. 2 is a sectional view partly diagrammatic showing the general arrangement of the compressor, the evaporator and the condenser; Fig. 3 is an enlarged sectional view of the compressor taken on the line 8`8 oi' Fig. 4;

Fig. 4 is a sectional view of the compressorY v taken on the line 4-4 of Fig. 3;

Fig. 5 is a sectional view taken on the line 5-5 of Fig. 3; Y

Fig. s is an elevational view of the ou sep-` arating unit; and

Fig. 'l is a fragmentary sectional view taken on line 'l-'l of Fig. 3.

Inasmuch as the ordinary garage is not equipped with refrigeration testing and refrigeration repair equipment and inasmuch as the average garage mechanic is not prepared to service refrigeration equipment, it is desirable to provide a completely sealed refrigeration unit in which no refrigerant lines are exposed for use in conditioning the air for private automobiles.

As shown in Fig. 1, I. have provided a refrigeration unitll which is adapted'to be mounted `directly within the engine compartment of' a conventional automobile. The unit l0 comprises a casing having a first section i2 which encloses a motor-compressor unit and a second section I4 welded thereto which encloses the refrigerant evaporator and the refrigerant condenser. inner casing I8 separates the condensing chamber I8 from the evaporator chamber 28. A water coil 22 is provided within the condensing'chamber' I8 and is adapted to be connected in series with the water cooling coil 24 mounted in front of the main engine radiator 26. A water pump 28 which is adapted to be driven from the fan belt 80 circulates the water between the water coil 22 and the heat dissipating radiator 24. Al

vwater chilling coil 82 is mounted directly within seat 40. A fan42 is provided for'circulating airto be conditioned in thermal exchange with the cooling coil I4. 'I'he conditioned air is discharge through the grill 44.

The compressor 48 is of the four vane rotary 1 type and includes la drive shaft 48 on which is s ventional construction.

varies 54 in proper position with respect to theI mounted a pulley 58. which also is adapted to be driven by means of the fan belt 80. 'I'he compressor comprises a four vane rotor element 52 which is formed integrally with the main shaft 48. Varies 54, which are of conventional construction are carried by the rotor 52 as shown. Each vane includes a shoe element 56 of con- Pins 58 maintain the walls of the main cylinder 80. The shaft 48 is journalled in the compressor end walls 8l and H0. The cylinder is recessed as at 62 so as to p'rovide an intake port for the compressor.-

very little space is available for any reserve sup- 4 ply of lubricant. i It is important, therefore, to provide some lmeans `for lubricating the ccmpressor bearings without depending -upon the accumulation of lubricant within the compressor compartment.l This is especially true in a system in which the compressor is required to operate at extremely high speeds for prolonged periods since under such conditions the lubricant is carried along with the high velocity gas flowing through the compressor. As best shown in Fig. 4, I have provided a lubricant entraining means comprising a porous sintered metal plate 68 which is secured to the outer wall of the cylinder 6D by means of cap screws iii. All of the compressed refrigerant together with the lubricant discharged from the compressor is required to pass through the porous sintered metal plate 58. The lower portion 'l2 of the plate 68 is treated such as by dipping in solder so as to close frigerant directly back to the compressor bearings in` a manner to be explained more fully hereinafter.

As shown in Fig. 3, the lubricant feed passage It communicates with branch lubricant passages 18 and 19. The passage 18 conveys lubricant to the main bearing surface 80. A passage 82 is provided in the main bearing surface 8u for distributing the high pressure lubricant along substantially the full length of the bearing surface 80. The passage 82 terminates at a point 84 which is close to the shaft seal cavity 88. A passage 8B is provided between the shaft seal cavity 86 and the compressor inlet port E2 whereby the shaft seal cavity B6 is maintained at a low pressure substantially equal tothe pressure within the evaporator. Inasmuch as the lubricant supplied to the 4passage 82 is at a pressure substantially equal to the high side pressure and inasmuch as the lubricant normally has an appreciable quantity o refrigerant entrained therein, it is apparent the restriction provided by the bearing 80 between the end of the passage 82 and the shaft seal cavity '36 serves the same function' as a fixed restricter provided between the high pressure refrigerant in the condenser and the lowpressure refrigerant in the evaporator. Thus the refrigerant contained by the lubricant which escapes into the shaft seal chamber 86 vaporizes and cools the shaft seal mechanism.

As shown in Fig. 3, the shaft seal mechanism comprises a rotating sealing ring 90 carried by the shaft 48. A neoprene gasket 82 provided between the ring 90 and the washer 94 prevents the escape of lubricant and refrigerant between varies very little throughout the major portion of the range throughout which the washers may be compressed. inasmuch as the end play in a compressorof this type is not very great, the spring washers are not required to be deformed beyond the range within which they offer a sub' stantially constant spring pressure. The rotating sealing ring cooperates with the stationary sealing ring 98 which is carried by the compressor end wall casting 6|. The sealing ring 8B is held in place by means of a washer element |09 which in turn is held in place by means of one or more cap screws lill. A neoprene gasket |92 serves to resiliently support the sealing ring 9@ so as to allow the ring 88 to adjust itself to the rotatable ring 90. A fitting |04 which may be brazed or otherwise secured to the casing section l2, is provided which makes it possible to remove the cap screws |0| and the shaft seal I mechanism without much diiiiculty. The gasket |02' also provides a refrigerant and lubricant tight joint between the fitting |04 and the washer IDE.

By virtue of the small space required by the shaft seal mechanism, the distance from the main bearing B0 to the end of the shaft d8 is so small that it is ,not necessary to provide an external bearing for the vcompressor operating shaft d6.

One or more passages such as the passage M6,v

shown in Fig. il,v allows the compressed gas to fiow from the compressor casing l2 into the condensing chamber IB in which the compressed gas condenses when coming in contact with the water coil 22. The condensed refrigerant collects in the lower portion of the condensing chamber Ill and is supplied therefrom into the evaporator chamber 20 through the capillary tube I0@ which serves as a fixed restrictor. The liquid refrigerant thus flowing into the evaporator chamber 20 evaporates therein and serves to refrigerate the water flowing through the water coil 32. Inasmuch as the lspeed of the automobile engine and therefore the speed of the compressor bears no relationship to the refrigerant requirements, it will frequently happen that the refrigeration system has excess capacity and that alarge amount of liquid refrigerant will accumulate within the evaporator chamber 20. The speed of the compressor may be so great at times that it becomes necessary to allow a portion of the liquid refrigerant in the evaporator chamber 2i) to enter the inlet of the compressor so as to vcool the compressor and supply the necessary lubrication to the compressor. Accordingly, the end plate I IU of the compressor is provided with a circular recess H2 which communicates with the suction port 82 of the compressor through a plurality of passages ile (see Figs. 3 and 4). Plate member ||6 is secured to the compressor end plate ||0 by means of the bolts |24 and is provided with a plurality of apertures I8 through which refrigerant in the evaporator chamber 2Q may return to the compressor inlet 62. A screen |20 is provided for filtering the refrigerant re" turning to the compressor and for partially restricting the fiow of liquid refrigerant through the apertures IIS. The screen |20, being a fine mesh screen, affords considerable restriction to the iiow of liquid refrigerant therethrough.

The arrangement of the apertures H8 is such that under certain conditions, the level of liquid refrigerant within the evaporator chamber 2|! will be below the lowermost aperture I I8.

A gasket |28 of neoprene or some similar material which is relatively unaffected by the lubricant or the refrigerant, is clamped between the ring III and the 'compressor end plate H0. The gasket |28 provides a. refrigerant tight seal betweex the 'refrigerant in the casing section I2 er casing I2.

y2,361,855 i v 3 and the refrigerant in the condenser chamber I8. By virture of this arrangement, it is not necessary to `weld or otherwise fasten the compressor end plate IIB on the ring IIS to the out- The advantage of this construction is that relative movement between the compressor end plate I| and the casing I2 is permitted. Such an arrangement has considerable merit in that it allows for unequal expansion and contraction of lthe various parts due to the changes inthe temperatures. The inner casing section I6 isspaced from the outer casing Il by the block I'I (see Fig. 2) which is hydrogen brazed or otherwisel secured to the casing sections I4 and I6. An adapter ring |28 secured to the plate IIS by means of cap screws |30 carries a neoprene gasket |32 which has a tapered outer surface adapted to engage the inner end of the casing I6 which is also tapered as at |34 so as to insure a tight seal. A neoprene sealing ring |36 is provided between the plate IIB and the ring |28.

The compressor end plate I I0 is provided with a' shaft bearing extension |38. The one end of the bearing |38 is exposed to the low pressure refrigerant within the refrigerant chamberv 20 whereby the high pressure lubricant supplied to the bearing through the passage 'I9 will find its way along the full length of the bearing |38. The

overflow into the .compressor housing I2. This is a distinct advantage in that at these low speeds it is important to keep the evaporator reasonably free of lubricant so as to make fullest use of the evaporator. Thus, in hot weather. when it is important to have greatest evaporator eiliciency when the compressor is required to operate at slow speeds, the evaporator will be relatively free of lubricant.

At high compressor speeds, the lubricant will tend to collect in the evaporator so as to reduce the evaporator eiilciency. n'der this condition an increased amount of oil will be carried along with the refrigerant vapor to the compressor. This not only'provides the increased amount of lubrication required but alsoserves to reduce the cooling capacity of the system. The reduced ca pacity is caused by the fact that the lubricant returning to the compressor will have a considerable quantity `of 'unevaporated refrigerant entrained therein which reevaporates upon entering the compressor. The greater the compressorspeed the greater will be the velocity of the gas whereby a greater amount lof lubricant and unevaporated refrigerant will be swept along with the gas returning to the compressor.

The arrangement of the evaporator with re` spect'to the condenser serves to 'compensate for the changes in the compressor speed. The-pres` ence of liquid refrigerantl in the evaporator at high compressor speeds and consequently high head pressures, helps to condense the refrigerant in the condenser and thereby reduce'the head -lJ-Iessure. 2

While the forml of embodiment of the invention as herein disclosed, constitutes a preferred form,

it is to be understood that other forms might be.

adopted, all coming within the scope of the claims which follow.

What is claimedis asfollows:

1. Air conditioning apparatus comprising in combination; a casing; a compressor within said casing having an inlet port and an outlet port; a compressor operating shaft having one end projecting through one wall of said casing; means carried .by said projecting end of said shaft for rotating said shaft; means forming a shaft seal cavity adjacent said shaft; shaft seal means within said cavity cooperating with said casing and said shaft for'preventing the escape of lubricant along said shaft; a porous sintered metal oil separating element adjacent the outlet of said compressor; means cooperating with said porous ele-` ment. for collecting the lubricant separated out thereby; means for supplying lubricant from said lubricant collecting means to said shaft seal cavity; means providing a passage between said shaft seal cavity and the inlet to said compressor, a wall memberwithin said casing through which the other end of said compressor operating shaft projects; means cooperating with said wall mem-v ber forming an evaporator chamber adjacent said other end of said shaft; means for condensing lthe refrigerant compressed by said compressor;

means for supplying condensed refrigerant at a reduced pressure to said evaporator chamber; and meansfor circulating an air cooling medium in thermal exchange with the refrigerant in said evaporator chamber and in thermal exchange with air to be conditioned.

2. Air conditioning apparatus comprising in combination a casing; a compressor within said casing having an inletl port and an outlet port; a compressor operating shaft having one end projecting through one wall of said casing; means carried by said projecting end of said shaft for rotating said shaft; means forming a shaft seal cavity adjacent said shaft; shaft seal means within said cavity cooperating with said casing and said shaft for preventing the escape of vlubricant along said shaft; said shaft seal means comprising a stationary sealing ring resiliently' supported by said casing, a rotatable sealing ring resiliently mounted on said shaft, and resilient washer means biasing said` sealing rings into engagement; a porous sintered metal oil separating element adjacent the outlet of said compressor; means cooperating with said porous element for collecting the lubricant separated out thereby; means for supplying lubricant fromsaid lubricant collecting means .to said shaft seal cavity; and means providing a passage between said shaft seal cavity and the inlet to said compressor; a wall member within said casing through which the other end of said compressor operating shaft projects; means cooperating with said wall member forming an evaporator 4chamber adjacent said other end of said shaft; means for condensing the refrigerant compressed by said compressor; and means for supplying condensed refrigerant at a reduced pressure to said evaporator cham- I 'i in.` said cavity cooperating with said casing and along said shaft; a porous sintered metal oil separating element adjacent the outlet of said compressor; means cooperating with said porouselement for collecting the lubricant separated out thereby; lmeans for supplying lubricant from said lubricant collecting means to said shaft'seal cavity; means providing a passage between saidshaft seal cavity and the inlet to said compressor, .a wall member within said casing through which the other end of said compressor operating shaft projects; means cooperating with said wall member forming an evaporator chamber adjacent said other end of said shaft; means for condensing the refrigerant compressed by said compressor; means for supplying condensed refrigerant at a reduced pressure to -said evaporator chamber; and means for circulating an air cooling medium in thermal exchange withv the refrigerant in said evaporator chamber and in thermal exchange with airto be conditioned; said means for concomprising a. ,plurality of openings leading from said evaporator chamber to the inlet of said compressor, and means cooperating with said openings restricting the now lof liquid refrigerant and lubricant through said openings.

7. In combination, a casing, a compressor within said casing including a compressor operating shaft and bearing means for said'shaft, means forming a condensing'chamber Within said casing, means forming an evaporator chamber within said casing, refrigerant and lubricant now connections between said compressor, said condensing chamber and said evaporator chamber,

fpressor, means cooperating with said openings densing the refrigerant',l comprising aclosed heat Vtransfer system having a heat absorbing element arranged in thermal exchange with the refrigcharged from 4said compressor along with the I erant to be condensed and having a heat dissipatcompressed refrigerant, means for feeding said lubricant to said bearing means, means for returning the lubricant supplied tothe one end of said shaft to the inlet of said compressor, and

means for draining the lubricant supplie'd to thev other end of chamber.

5. Ina refrigerating system having a compres.- sor adapted to be -operated at widely varying said shaft into said evaporator speeds irrespective of refrigeration requirements,

acasing, means for dividing said casing into a l plurality of compartments, refrigerant compressing mechanism within one of said compartments having an inlet port and outlet port, a compressor l s operating shaft projecting through' said casing, a shaft seal for said shaft, means enclosing said shaft seal, lubricant separating meansadjacent said outlet port, means for supplying lubricant from said separating means to said shaftseal enclosing means, vmeans for returning lubricant from said shaft seal enclosing means to the inlet of said compressor, means. for condensing refrigerant within one of said compartments, means for evaporating refrigerant in anotherfof -said compartments, means for supplying refrigsaid refrigerant and lubricant iiow connections comprising a plurality of openings'leading from said evaporator chamber tothe inlet of said comrestrcting the now of liquid refrigerant and lubricant through said openings, said refrigerant a compressor within said casing having an inlet port and an outlet port; a. compressor operating shaft having one end projecting Vthrough one wall of said casing; means carried by said projecting end of said shaft for rotating said shaft; means forming a shaft seal cavity adjacent said shaft; shaft seal means within said cavity cooperating with said casing and said shaft for preventing the escape of lubricant along said shaft; a porous sintered metal oil separating element Aadjacent the outlet'of Ysaid compressor; means cooperating with said porous element for collecting the lubricant separated out thereby; means for'supplying lubricant from said lubricant collecting means to said shaft seal cavity; means providing a passage between said shaft seal ca vity and the inlet to said compressor, a wall member within said casing through which the other end of said compressor operating shaft projects:

and means cooperating with the said wall member forming a low pressure refrigerant chamber adjacent said other end of said shaft whereby said other end is cooledby the evaporating refrigerant.

9. Air conditioning' apparatus for use in an automobile 'comprising in combination; a casing;

a compressor Within said casing having an inlet port and an outlet port; a compressoroperating shaft having one end projecting through one wall of said casing; means carried by said projecting y end of said shaft for'rotating said shaft; means etant condensed in said one compartment to said evaporator compartment at a reduced pressure.

means for conveying refrigerant from said evaporator compartment to said inlet port, and means for conveying compressed refrigerant from said outlet 4port to said condenser compartment.

6. In combination, a casing, a. compressor with'- in said casingincluding a compressor operating shaft and bearing means for saidshaft, means forming a condensing chamber within said Acasing, means forming an evaporator chamber within said casing', refrigerant and lubricant` flow connections between said compressor, said-oon-- densing chamber andsaid evaporator chamber,

said refrigerant and lubricant flow connections forming a shaftseal cavity adjacent said shaft; shaft seal means within said cavity cooperating with said casing and said shaft for preventing the escape of lubricant along said shaft; a porous sintered metal oil separating element adjacent the outlet of said compressor; means coop` erating with said porous element for collecting the lubricant separated out thereby; means for supplying lubricant from said lubricant collecting means to said shaft seal cavity; means providing a passage between said shaft seal cavity' and the inlet to said compressor whereby'refrigerant entrained by the lubricant evaporates to cool said shaft and shaft seal means, a wall member within said casing through which the other end of said compressor operating shaft projects; means cooperating with said wallmember form-l ing a low pressure chamber adjacent said other end of said shaft; and means for supplying refrigerant and lubricant at a reduced pressure to said chamber.

10. In combination, a casing, a wall member within said casing, a compressor, a compressor operating shaft, bearing means for` said shaft provided in said casing and said wall, means cooperating with said wall forming a low pressure chamber inwhich oil may collect, means for collecting lubricant discharged from said compressor along with the compressed refrigerant, means for feeding said lubricantto said bearing means, means for returning the lubricant supplied to the one end of said shaft to the inlet of said compressor. and means for draining the lubricant supplied to the other end of said shaft into said chamber.

1l. In combination, a casing, a compressor within said casing including a compressor operating shaftand bearing means for said shaft, means forming a high pressure chamber within said casing, means forming a low pressure chamber within said casing, refrigerant and lubricant flow connections between said compressor, said high pressure chamber and said low pressure chamber, said refrigerant and lubricant flow connections comprising a plurality of openings leading from said low pressure chamber to the inlet of said compressor, and Ameans cooperating with said openings restricting the flow of liquid refrigeran and lubricant through saidopenings.

12. In a refrigerating system, a casing, refrigerant compressing mechanism within said casing having an inlet port and an outlet port, a com-` pressor operating shaft projecting through said casing. a shaft seal for said shaft, means enclosing said shaft seal and forming a shaft seal cooling cavity, a lubricant separating means adjacent said outlet port, means for supplying lubricant from said separating means to said shaft seal coolingl cavity, means for connecting said shaft seal cooling cavity to the inlet port of. said compressor, means for condensing refrigerant, means for evaporating refrigerant, means for supplying condensed refrigerant to said evaporator at a reduced pressure, means for conveying refrigerant from said evaporator to said inlet port, and means for conveying compressed refrigerant separated from said lubricant to said condenser.

13. In a volatile refrigerant system, an evaporator, a condenser. a compressor, refrigerant now connections between said evaporator, condenser and compressor, said compressor having a compressor operating shaft-and a bearing therefor.

rotating said shaft; means forming a shaft seal cavity adjacent said shaft; shaft seais means within said cavity cooperating with said casing and said shaft for preventing the escape of lubricant 'along said shaft; a porous sintered metal oil separating element adjacent the outlet of said compressor; means cooperating withsaid porous Velement for collecting the lubricant separated out thereby; means for supplying lubricant from said lubricant collecting means to said shaft seal cavity; means providing a passage between said shaft seal cavity and the inlet to said compressor; means forming an evaporator chamber; means for condensing the refrigerant compressed by said compressor; and means for supplying condensed refrigerant at a reduced pressure to said evaporator chamber.

,15. Air conditioning apparatus comprising inl combination; a casing; a compressor within said casing having an inletiport and an outlet port; a compressor operating shaft; means for rotating said shaft; means forming a shaft seal cavity adjacent said shaft; shaft seal means within said cavity cooperating with said casing and' said shaft for preventing the escape of lubricant along said shaft; said shaft seal means comprising a stationary sealing ring resiliently supported by said casing. a rotatable sealingring /resiliently mounted on said shaft. and resilient washer means biasing said ,sealingt rings inton engagement; a porous slntered metal oil separating ele ment adjacent the outlet-of said compressor;

means cooperating with said porous element for collecting the lubricant separated out thereby; means for supplyinglubricant from said lubricant collecting means to said shaft seal cavity;

a shaft seal for preventing the escape of lubricant and refrigerant from said bearing to the outside atmosphere, means forming a cavity surrounding said shaft seal. eans for supplying lubricant containing refrigerant under pressure to said shaft seal cavity comprising a lubricant supply passage having a fixed restriction adjacent the outlet thereof into said shaft seal cavity. and means for maintaining said cavity at a pressure lower than the pressureof the lubricant and refrigerant supplied thereto whereby the refrigerant evaporates and cools said shaft seal.

i4. Air conditioning apparatus comprising in combination; a casing: a compressor within said casing having anl inlet port and an outlet port; a compressor operating shaft having one end projecting through one wall of said casing: means and means providing a passage between said. shaft seal cavity and the inlet to said compressor;

means forming an evaporator chamber; means for condensing the refrigerant compressed by said compressor: and means for supplying condensed refrigerant at a reduced pressure to said evaporatorchamber.v

i6. In a volatile refrigerant system; an evaporator; a condenser; a compressor; refrigerant flow connections between said evaporator. condenser and compressor: said compressor hav.-

- ing a compressor operating shaft and a bearing therefor; means forming a cavity adjacent said shaft; means for supplying lubricant containing refrigerant under pressure to said cavity comprising a lubricant supply passage having a nxed restriction adjacent the outlet thereof into said cavity; and means for maintaining said cavity at a pressure lower than the pressure of the lubricant and refrigerant supplied thereto whereby the refrigerant evaporates so as to produce a cooling eect.

17. In a volatile refrigerant system; an evaporator; a condenser; a refrigerant compressor having. an in'letport and an outlet port and hav- 1 ing bearing means lubricated by means of lubricant flowing through said compressor; refriger- Y ant flow connections between said evaporator.

carried by said projecting end of said shafttfor condenser and compressor; and voil separating means located adjacent the outlet port comprising a vporous sintered metal member through which thel compressed refrigerant together with any entrained lubricant is required to pass before the compressed refrigerant flows to said condenser; and means for collecting the lubricant thus separated from the refrigerant and for returning the lubricant to said bearing means.

. ALEX A. HcCORMACK. 

